When the mishkan was built, HaShem did not levy it. Exodus 25:2 says take an offering from every man whose heart moves him, and Exodus 35 records what came in: gold, blue and purple and scarlet yarn, acacia wood, spun goat hair, tanned skins, and skill in the hands of anyone who had it. The dwelling place of HaShem was assembled out of the whole community's offerings, and no single offering was the building.

Nadiv is from the root nadav, to volunteer, to give freely, and the same root gives Hebrew its word for a noble. The willing man and the noble man share a word. I hold that as resonance rather than argument, but it is worth sitting with, because our instinct is to think nobility is a rank and willingness is a temperament. In Hebrew they grow from the same place.

Nadiv lev is therefore not a personality type. It is a decision made in the lev, the seat of will, to bring the piece you carry into the room instead of keeping it back. No contribution too small. None of them the whole thing.