In Warhammer 40k, psykers are the ideological equivalent of wizards in the Age of Sigmar. When I began working on the Tyranid and Space Marine warscrolls, I realized that I would have to address the difference between psykers and wizards. What I ended up deciding on was that a psyker would be mechanically identical to a wizard, but would use slightly different words. I ended up with the following:
[Model Name] is a Psyker. It can cast one psychic power in each of your hero phases and attempt to unbind one psychic power in each enemy hero phase. It knows the Psychic Bolt, Mystic Shield, and _______ powers.
I kept the wording as nearly identical as possible so that it would be clear (hopefully) that Psychic Bolt is the same thing as Arcane Bolt. Mystic Shield did not need a re-flavoring because it already sounded like a psychic power. Which brings me to the Chaos Sorcerer.
When I began working on the Chaos Sorcerer warscroll for Chaos Space Marines (one of my friends requested CSM, so the Space Orruks will have to wait a little longer) I had originally planned to continue with the Psyker keyword. But I realized something, only Chaos Wizards can summon Daemons. I decided that even though it sets the Chaos Sorcerer off a little from the rest of the 40k warscrolls, I feel like their pre-existing ability to summon Daemons trumps that particular consistency.
The next followup is, the Chaos Sorcerer can attempt to unbind one spell per enemy hero phase. A Hive Tyrant doesn't cast spells, it casts psychic powers, and it can attempt to unbind one psychic power per enemy hero phase. Since Psychic Bolt is a psychic power, and arcane bolt is a spell, can a Chaos Sorcerer attempt to unbind Psychic Bolt? Can a Hive Tyrant attempt to unbind Arcane Bolt? I'm afraid that's up to you players. This will just have to be one of those unanswered questions of Age of Sigmar. Since the wording is pretty clear, I can definitely see where they would not, and since the door swings both ways (by gaining the ability to never be unbound, you can also never unbind), I'm not too worried about players gaining an unfair advantage from something like this.