The nuance between the two sentences is subtle but present:
1. "Are we going to get off the next stop?" - This phrasing suggests a future plan or intention. It's asking if, in the future, the action of getting off at the next stop is going to happen or if it's part of the plan.
2. "Are we getting off the next stop?" - This phrasing suggests a present decision or immediate future action. It's asking if the action of getting off at the next stop is currently under consideration or if it's going to happen in the near future.
So, while both sentences essentially ask about the same action, the first one focuses on future intention or plan, while the second one focuses more on the immediate decision or action.