A matter of order?
While seeming like an easy question, it might actually be a bit more convoluted.
The way I see it, the question comes down to the order of following two aspects:
- Regaining actions
- Regeneration bringing the creature above 0 HP
On the subject of gaining actions:
Single actions can be completed in a very short time. … During an encounter, you get 3 actions at the beginning of your turn, which you can use as described on page 468. Core Rulebook pg. 461 errata 4.0
Archive of Nethys
On the subject of regeneration:
A creature with fast healing or regeneration regains the listed amount of Hit Points each round at the beginning of its turn. Core Rulebook pg. 461 errata 4.0 Arcive of Nethys
Thus: does the unconscious dying creature regain hit points before regaining its actions, and thus can it act on its next turn?
Best Answer
Yes
Actions are gained after all other "start/beginning of turn" effects