Flying into the USA is a different story when it comes to flight connections.
As soon as you touch US soil, you are required to go through immigration and customs (unless you’re flying in from
Dublin where they do this pre-departure).
She’ll disembark and then go together with everyone to passport control. This can be a 10 min or a 2 hour wait… depends on the day of the week, time of day and terminal as to how staffed they will be. For New York I usually fly into Newark and I’ve both walked through within minutes, or had to wait hours in an unventilated cramped area. Tell her to refill her water bottle and use the toilet before getting off the plane, just in case.
After getting through immigration, she’ll have to collect her luggage and go through customs (mostly non-existent nowadays, but they might give a slip of paper to complete on the plane. You hand this in to the officer). She then proceeds outside of international arrivals area per se.
After coming out of immigration / customs, there will usually be a dedicated area to drop off bags for connecting flights. Very rarely do you have to queue again - these areas / belts are well signalled so she should be able to find them pretty easily.
If there is a change of terminal, she does that. Then proceed to security (again, there might be a dedicated line for those coming off connecting flights, if she’s lucky). Normal security check, except than in the US you always take shoes off too.
So to sum up, immigration first, then reclaim bags, walk through customs (maybe hand in a form, airline will tell them), drop bag off, change terminals if needed, clear security, go to boarding gate.
2 hours is on the tighter side but totally doable at most US airports, if she moves fast.
Check on her ticket if a change of terminal is required. Aim to sit as upfront in the cabin as possible, if she has the chance to select her seat ahead of time.