Yes, charges can be brought if your wife says that you pushed her down and that she hit her head, even if you assert that you did not touch her. Law enforcement has a statement from her that is corroborated by her nephew (although corroboration from someone other than your wife is not necessary). You have a differing account of what happened. Your daughter's version seems to be similar to yours. An attorney can help you by having an investigator conduct a thorough investigation. You need to stop discussing your matter in a public forum and find an attorney to help you.
Many attorneys charge nothing for a consultation. You need to talk with someone who handles domestic violence cases soon as possible. Good luck.
Has she already been to the police and made a report? if not, the answer is yes she can still go to the police department and bring charges but it will be very hard for the prosecution to prove their case. Unless she still has bruising or injuries on her, otherwise it will be very hard to prove. If you can fight this case, do it because a DV conviction will not only affect your custody battle but also has severe punishments. If she files charges against you, hire an attorney.
First, I'm sorry you're in this situation. I can't imagine how stressful it must be to know there are false accustions of this nature hanging over your head.
My colleagues are correct that your wife can file charges against you. It sounds like she's already made a police report. From that point, it's largely up to the police and the prosecutors what happens. I'm from Modesto, but I'm not sure what the department policy is with respect to requesting a police report. Perhaps start there to see what the contents of the police report are. Also, it's a good idea to consult an attorney who is familiar with the interactions between criminal charges of this type and child custody proceedings. It is entirely possible the police report will not result in any further criminal proceedings, but that doesn't mean her allegations won't have consequences. Be cautious and make sure you know what your options are in defending against these allegations.
Any and all responses to this and any other questions are intended for basic informational purposes only and are not legal advice.
False allegations are made all the time and unfortunately innocent people have to spend time and money defending themselves agains false allegations. I recommend not talking about your case with anyone, including the police if they approach you. You don't have to speak to the police. Don't admit anything you may feel regretful for. Stay calm and seek counsel with an attorney to help you sort things out. Often times doing less is better than trying to control the situation.
The answers offered by this attorney are for general information purposes only and you should not take action based on these answers without first speaking with an attorney who can go over all the facts of your case in person. Every case is different; a change in facts results in a different answer.