Nope, DI only grants swift actions.
Pun-Pun can, at least, use multiple ToB Counters in a round through that Diamond Mind stance.
Pun-Pun can sort of fake NI immediate actions, though. Whenever he's done using one immediate action, he can use a readied action to cast Time Stop, which gives him 2-5 turns. The important part is that when the TS ends, he's on a new turn, so he has a new immediate action again. Rinse and repeat.