If you use the search function you’ll find a few threads about Nebraska mule deer in here. I’ve hunted Nebraska quite a bit. Go into it with an open mind and low expectations and just try to have fun. expect a lot of pressure.
Good chance you’ll see more whitetail than mule deer so don’t get stuck on the one species. It used to be the opposite, but the last 10 years have not been good to mule deer here. It’s not completely doom and gloom, guys do take nice deer off public every season. Just have realistic expectations.
My best advice is pick a unit & start scouting!! Water, cover, food etc. google earth is great tool as you can scout areas from your computer that look good. The key is scout as much as you can to find a honey hole. You will find most guys are not going to give you specific units, but instead give advice such as this. The units up there are good in September & the desert units are good in January you just got to pick a unit & start learning as best you can. If you don't find any deer or sign move on to another area & so on. hope this helps & good luck!!