Check out this thread for info you are looking for.https://texashuntingforum.com/forum...itetail-nilgai-hunt-any-info#Post7260093
I hunted it in January of 18. I think there was only one taken when we hunted and I didn't get to hunt hard as I had my wife and son with me, wore their legs out. Really cool place, saw lots of deer.
Get as far from the roads as you can, NW corner was where they were reported when I was there. If I ever draw again I will have a bike with a tow behind cart. Permethrin on your clothes and a good bug repellent even in January. Cold front blew out our first day and it was 70's after that.
Put a stout bullet in the right place and they will go down just like anything else. Google their vitals and CNS. Practice, practice practice. Shots won't be far unless you want to, it is pretty thick with few high spots. There is some coastal prairie that is 5-600 yards of open space. I several deer less than 200 yards and could have easily closed the gap with the cover there.
Good luck, I'd hunt it again in a heartbeat!