I think there is but just a mild one. I mean, just flirting. Coz it mentioned that in his previous life his beloved died early, even before he got started to become strong. Because of the Glory City's destruction. After that he just wandered through the world to become the strongest.
There is some but not enough to be in your face front and forward. More about NL gaining power and getting bigger and better.(currently up to date with novel so..)
Before I deep dive, can anyone tell me if there is romance in this manga or like hints cause I really don’t want any romance >_<