Thank you! I've been a Mario (and Mario artwork) devotee for a long time.
Nakaue is a Nintendo staffer focused on artwork and artwork supervision. Just about all his credits are for Mario games, including big titles like 3D Land, 3D World, Mario Kart 8, etc. You could say 3D Land was his "debut" as lead Mario artist emulating the Kotabe style perfectly, but he's credited with art supervision and artwork for earlier games that are a little more stylized (like Mario vs Donkey Kong 2 and Super Mario Strikers).
Kotabe has actually been retired for more than a decade, and probably spent his last few years at Nintendo mentoring Nakaue during his first few years there!