Only unit it cud realistically be paired with is AT and other stealth units; dont pair it with non-stealth units, unless its for baiting (1 mot inf lvl 1 + 6 militia lvl 3 in forest wud be a nasty surprise).

Send militia forward in front of other units to take unguarded provinces, surprising the enemy if they don't have scouts...

Make sure to skip upgrade militia; lvl 1 --> 3 or 4 preferably

Oh and refer to @K.Rokossovskis militia guide: The Militia Guide

Anti Tank and Milita and AA spam is slept on. Nothing can beat it once you have enough. Maybe add some artillery in, actually. Rocket artillery can probably win. Guess it’s back to militia and anti tank lol. Get some interceptors.

If its in a non-plains province with no enemy scouts (like ACs, mot inf, and ints) nearby, then yes, it cud work. Its a bad example tho, since its vulnerable to air dmg. Switch the mot inf for 2-3 AA; that shud do the trick. Maybe pair with AT as well if in forests or cities.