My 16 month old is aparently lactose intolerant having loose stools she's taking whole milk, tried lactaid & cause constipation, can she take nutramigen?

Yes but: Nutramigen should be tolerated but there may be other choices. Check with the pediatrician for the best solution to the problem.

Pricey solution : Soy based milk like products are lactose free & much less expensive.. A 16 mo cam also get all the calcium they need from a couple of tum's /day & just drink water. The other stuff in milk can be made up by a diverse diet.