A nested action is an action within an action. This does not happen in this game as the current action resolves before another action is taken. This includes queue for the current action, it is finished when that action ends. Jango's ability is contained within the action of Rey's activation. The other actions granted by abilities (those abilities are resolved in the queue but the actions they grant are taken as separate actions) happen preceding, but not within, Rey's activation action. Yes, I did nest a sentence within a sentence there.
So there is an ability that grants an additional action and then there is the actual action. The ability gets resolved but the second action is not resolved within that action, it is simply granted and then taken after the current action is fully resolved.
Example: Tactical Mastery is played, queue - pay one resource for cost of card, queue - spot a red character, queue - event- take up to 2 additional actions. Action ends, queue is ended. Current player still has two more actions to take, each with separate queues as actions get fully resolved before another action can be taken. This card allows for 3 consecutive actions by one player. One of those actions may be to activate a character and if Jango is playing opposite, he could activate within the action the character activates in, not one of the other 3 actions.
We may be saying very similar things, just in different ways. However, the queue would not extend to multiple actions, and thinking it does, would cause this confusion.