Competitive Guide: Navighast

[Dragonstrike]

So, since I'm currently training a competitive Swabone that has been laying in my in-game boxes since like...months for the sake of bringing up a Navighast with Leaf Blade on the upcoming Tournament, I was wondering how to implend that move on the Physical Set? I'd enjoy to keep Swords Dance and take Leaf Blade instead of Ice-Punch/Knock Off on the fourth move slot, but wanted to hear whether this would be a well choice at all. 

Swabone in question has an adamant nature and I plan for using Mach Punch as its Priority STAB alongside Shadow Claw for second STAB, wearing an Expert Belt.

I'd say Leaf Blade would be a surprise coverage move more than anything else.  How effective it will be will depend on how many Ground and/or Water types weak to Grass you think you can catch off guard with the move.  Could have some merit as a kind of middle ground between Ice Punch and Thunder Punch since you hit both Ground and Water types rather hard with it at the expense of being more likely to lose to some other threats (Gliscor, Cocancer, and non-mega Gyarados in particular come to my mind).  

You do also get to surprise KO Escartress that think they can take the neutral hit as well, which can be fun.  Dragon, Grass, and Flying types become a bit harder for Navighast to deal with in exchange, so plan accordingly.