can a stack of ola use side step to unstack?

I'm sorry I don't know what you mean by ola. Can you please clarify your question and if possible quote the exact power/ability/character in question.

orange lantern absorbed (or whatever) I think

RB page 23:

If a stack has not yet been assigned an action token during a turn, an individual horde token in the stack may unstack. Give the horde token a move action to leave the stack and move away. When a token leaves a stack, any game effects affecting the stack no longer affect the token.

PAC:
SIDESTEP
Give this character a free action; it can move with a locked speed value of 2.


So unless the Orange Lantern's have some special wording that specifically overrides the normal unstacking rules (which is why it always a good reason to quote the effects in question), then you can't use Side Step to unstack, To unstack, you have to give the horde token a move action specifically to do so (which means you can't use a move action to activate something else, like Phasing/Teleport); Side Step meanwhile, isn't even activated by a move action but by a free action.