We (humans) don’t need atmospheric nitrogen to survive, we just need the “other” in the atmosphere to not be toxic. My guess is any element in the same periodic table column as nitrogen that could somehow exist as a gas at STP would be fine (hypothetically).
Don’t they replace nitrogen with like helium for some SCUBA applications?
Other life on Earth obviously does metabolize nitrogen (I think we do a little bit too). So to preserve our biosphere we should not throw off the nitrogen balance. But as others have observed it’s not clear there’s any imbalance coming.