Yeah, Nobunaga already knows he has strong feelings for Natsu though it’s not quite sure what those feelings are yet so he doesn’t want to meddle directly since Ken’s going at his own pace with that as he always does.
Remember back when Ken and Mori senior went to get guns from Sakai/the border and Ken brought home bread? Nobunaga asked if he was living with Natsu since Nobunaga ordered a bunch of smiths to come to Gifu with Natsu being one of them but Ken said no since the whole goddess of the forge thing and Nobunaga thought he was being rather patient with it and determined to see it through.
Chapter 38
Basically Nobunaga knows Ken is satisfied and happy right now. Interfering with that would just cause resentment and trouble neither of them want so it’s keep Natsu happy, keep Nobunaga’s stomach and best diplomatic tool happy.