This Seeking Tech guide will explain how you can beat Nidhog in Astro Bot. Use the following video as a reference:
To start the fight, throw your axe at the hog.
Once he charges at you, run horizontally to avoid getting run over. Afterwards, throw your axe at the metal-band at his backside, and then call your weapon back.
You then need to back off and then wait until he rushes you again. He will move faster than before, so make sure you sidestep his attack. Afterwards, use your axe on his backside.
You should then back off to give yourself some distance, since Nidhog will charge at you at even greater speed. After dodging his attack, use your axe one last time to expose its tail.
Grab his tail, and then pull on it. Once you begin to have Nidhog on a spin, throw him towards the ice to complete the fight.