im in the divide and i want the NCR power armor on the 15, but i have to blow up the NCR, right? they idolize me right now, so if i do nuke them will i be villified? i really want that armor, but i dont want to be killing everyone on the strip because they hate and attack me.

You will become a "wild child" if you nuke them, not low enough to make them hostile.

You'll go to the "Wild Child" Status. They'll still like you though.