On auto, she's better, because you can't control Warchief's targeting. On manual, she's generally harder to use if she is your only provoker, because you can't easily control whether Decay has five debuffs, but provides much more value overall than Warchief does.

should she change the hydra team you suggested a while back ? Or should she go in 2nd hydra key team ?

The one I gave you here ?

If so, I think she's a decent candidate to replace Warchief for that team, yeah. You've got a lot of debuffs coming from everyone else, so you shouldn't need to rely too much on her own ones. Might require a few restarts to get the initial ball rolling, but especially on manual, it should work well.

I love Kantra, absolute staple of my NM team but as Kram pointed out she needs a bit of support.  Also I recommend running a back up provoke option if youve got one.  Husk works really well since he doubles as a damage dealer, or someone in a provoke set.

Husk would work great since i have 2 built (2 gnuts too and sadly no acryzia :P)

No room on your team. Put ukko in provoke.

Provoke Pig is a great option.

doubt i have a decent provoke set stat wise but will be on the lookout for it 

That's the nice thing about using it on Ukko. She only needs two other stats - SPD and ACC. So you've a lot more flexibility in terms of pieces. You can even resort to some 5-star pieces, really.