recommendation for hotel near miller park
It depends how you define near. There are no hotels within walking distance, per say. Most visitors prefer to stay downtown where you can get shuttles, buses, Uber or an easy drive to Miller Park. Staying downtown provides a good base for dining and other options and is especially important if you won't have a car.
Just stay downtown and either Uber to the game or take advantage of a shuttle from a bar... my favorite is the Milwaukee Brat House but there are others (do a Google/TA Forum search and you'll find some other options).
There's nothing major to do within walking distance of MP.