The HarleyWing ship is canon, I think, meeeting incidentally or even adversrially and then boning like the entire rabbit population of the warren’s future depends on it before Grayson gets embarassed again and they part ways while Nightwing gets disappointment vibes from Batman.

So it’s entirely appropriate for Harley to make thirsty jabs at Nightwing at any time.

At least Nightwing hasn’t yet been a jerk to Harley.