Lisa Roberts, 28, claims three-year-old Connie-Mae Sherratt "could have died" after she became pinned underneath the bookcase when she was left unattended.
She said staff phoned her to say Connie-Mae has been involved in an accident at nursery on October 11 but not to rush in as "she was fine".
They explained how the youngster had managed to clamber up the bookcase which then toppled on top of her at Ash Tree Day Nursery, in Chester.
But when Lisa arrived to collect her daughter she says she was horrified when she saw the extent of the swelling around her little girl's eye.
She took Connie-Mae to the doctors who said she may have suffered a concussion and she has since undergone x-rays and hospital check ups.
Lisa, of Blacon, Chester, claims she had no choice but to withdraw her daughter from the nursery, despite her "loving it" there and having lots of friends.
She said she found it shocking how five members of staff had failed to notice Connie-Mae climbing the bookcase after leaving her unsupervised for "over a minute".
Full-time mum-of-two Lisa added: "It is incredibly distressing to know my three-year-old daughter was left unsupervised long enough for this to happen.
"She could've lost her vision, or it could have a broken cheekbone, nose or eye socket.
"She could've died. She's one of the oldest and biggest children in the class "For a smaller child it could've been fatal.
"Her eye is still bruised ten days on. Pictures do not do it justice."
Lisa said she dropped Connie-Mae off off at 9.30am that day and received a phone call at 9.47am.
She added: "I was told that I didn't need to rush as she was fine and so I arrived approximately 30 minutes after the phone call.
"If I had known how bad it was I would have got a taxi to her straight away.
"I arrived at the nursery around 10.30am and was told that Connie's injury was worse earlier and that it had gone down.
"They also informed me that Connie had slept for 15 minutes following the accident.
No one had administered medication or first aid either.
"When I saw my daughter, her eye was incredibly swollen and bruised.
"Although Connie seemed ok, I felt panicked and took her to the pharmacist to have her checked over.
"They said if her symptoms worsened to take her to the doctor's immediately.
"Yesterday she was complaining about a pain in the back of her head, so she's currently in hospital for a head x-ray. She was going, 'Mummy, my eye, my eye.' "Since the injury she's been clingy which is out of character. She's usually far more confident.
"The doctor said hopefully it's just concussion, but it could be a skull fracture or a bleed on the brain.
"She couldn't sleep for days after and I kept her in my room to keep an eye on her in case she was sick.
"She was on life support at four weeks old with a chest infection and in hospital for eight days. This is bringing all that back and it's very traumatic for me.
"I nearly lost her once and nearly lost her again.
"I haven't heard anything else from Ofsted or the nursery. I think people should be suspended until the investigation is completed.
"I don't think either of them is taking it seriously."
Lisa said she and her partner David Hayden, 39, returned to the nursery later to discuss the accident with staff and to view the CCTV footage.
She said: "Connie was unattended for at least a minute and it took 14 seconds for them to notice she'd fallen.
"She had pulled herself up the back of the bookcase and when she got to the top it tipped and landed on her.
"It looked as if she may have climbed it before or seen another child do so as she seemed to know what she was doing.
"I wanted to watch the CCTV to see what happened.
"I saw her climb the bookcase, hit her head and then it fell.
"I can't say if she was trapped under the bookcase because I had to look away.
"I'm pregnant now and I was in bits. I couldn't watch it, it was horrible.
"It should have been prevented if one of those five women had been watching my child.
"When your little girl is in someone else's care you expect them to be safe, even more so in a nursery.
"Before I had nothing but praise for the nursery. Connie was settled and had friends there.
"I'm devastated that I have had to remove Connie from the nursery she loved so much and now I fear putting her in any other nursery.
"I trusted these people to keep my child safe like any parent does and they have failed.
"It will be an ordeal for her to settle into somewhere new."
Jason Ashcroft, who owns and manages the nursery, has apologised to Lisa and said an investigation was underway.
He said: "We are entrusted with the safety of over 300 children, and that includes in many cases, the children of our own employees, including my own son, who is of a very similar age.
"With that trust, we must accept complete responsibility for any accidents that occur on our premises.
"This is why we go to extraordinary lengths to ensure each and every child is safe and surrounded by highly-trained and qualified staff, who have the experience to deal with any situation that may occur.
"There are however, times when accidents happen, and as the founder and owner of the nursery, it is my responsibility to ensure that they occur as infrequently as possible and that all
staff know what the protocols and procedures are, should an accident occur and that they follow them to the letter."
He said he had spoken with Miss Roberts and "apologised unreservedly" for what happened and explained he had taken "total responsibility".
Mr Ashcroft also said the nursery had contacted Ofsted and said they had removed the bookcase and contacted the manufacturer to find out why it might have collapsed.
He added: "All staff throughout the setting have been interviewed and reminded of their responsibilities to the children and left under no illusion as to how seriously we take an incident of this nature, and that following the investigation, disciplinary action will be taken, should it be deemed that anyone responded in anything other than a totally professional manner.
"We deeply regret that Miss Roberts and her daughter have suffered as a result of this accident, however we are extremely pleased that the little girl in question, is making a swift and full recovery."
A spokesman for Ofsted said: "We don't comment on complaints.
"However, we take all complaints we receive very seriously and assess them thoroughly to see whether further action is needed."