Miltank builds?

i have zero knowledge whatsoever. im jus curious if Miltank would be good for anything of competitive? are there any different types of builds for certain situations? suggestions for natures, movesets, anything of that sort.

Miltank in my opinion is quite the underrated Pokemon. It's decent in stats, in that it has good defenses (aside from special defense), and a surprisingly high speed stat, and access to recovery in 'Milk Drink'. I'd say the only problem with it, like most normal type Pokemon, is that it lacks good normal type STAB. For instance, it does get Double-Edge, but a generation ago it had Return, which was quite decent for a sweeper Miltank, it also has a poor special defense stat and attack stat, meaning that it can't kill too much, you'd need to use a few Work Ups to get damage up whilst running a sweeper Miltank with coverage like Play Rough. I'd run something like this:

Miltank @ Expert Belt/Leftovers
Nature: Jolly
Ability: Scrappy/Thick Fat
EVs: 252 HP/252 Attack/4 Speed

- Double-Edge
- Play Rough
- Thunder Wave/Stealth Rock/Toxic
- Milk Drink

This moveset is decent. You have an Expert Belt and Play Rough for more damage on Fighting types, Milk Drink for recovery, and Thunder Wave or Stealth Rock if you're baiting a switch-in. You can interchange Toxic if you're aiming for more of a staller on your team. If you want a bit more resistance against Ice or Fire attacks, Thick Fat is decent, I'd say the better option for normal coverage is Scrappy, so that you can hit Ghost types. Only problem with the set so far is that it lacks kill options, hence why you have stuff like Toxic.

Alternatively... you can run...:

Miltank @ Assault Vest
Nature: Jolly/Adamant
Ability: Sap Sipper
EVs: 252 HP/252 Attack/4 Speed

- Double-Edge
- Play Rough
- Earthquake
- Power-up Punch/Iron Head

Sap Sipper would be incredibly useful to boost the attack of Miltank, which was quite low. Earthquake is for coverage of steel types, and Power-up Punch (if it gets this this game) or otherwise Iron Head is just overall decent coverage. Really, what Miltank you'd want to run depends on what team you have, whether you need a tank, or another sweeper for your team. Btw, if you're planning to make an in-game competitive Miltank, you need to get Power-Up Punch/Iron Head from Gen 6. Assault Vest is useful to patch up Miltank's below average special defense stat.

Hopefully the movesets I've suggested will assist you in creating a moveset you'd like for your Miltank, or take one of mine that I made.

Miltank is better suited as Pokémon that can sponge hit thanks to Thick Fat as well as heal itself. This was the set used last gen:

Miltank @ Leftovers
Ability: Thick Fat
EVs: 252 HP / 236 SpD / 20 Spe
Calm Nature
- Stealth Rock
- Seismic Toss
- Milk Drink
- Toxic

Another option is going for a more physically defensive build with something like Body Slam to paralyse opponents.

I wouldn't use it in higher tiers as it's too passive and outclassed by other Pokémon who can do Miltank's job much better (Clefable and Chansey comes to mind) but it can be more successful in the lower tier like NU.