Sprezzatura. Luciano Barbera defines "sprezzatura" as detachment, quiet confidence, or low-key style.
Nicola has this in spades.
Let's not confuse sprezzatura, though, with refinement or perfection; Nicola is a little shaggy, a little raw, and if you saw his shoes, certainly a little quirky. Think Agnelli without the money.
If I was still single I would sign up to be his wingman. What is the Italian word for "wingman"?