Not that impressive imo.
Nakamura has only *ever* played chess and was already playing "kindergarten championships" at 5 years old, coached by his FM stepfather.
He has now had decades of coaching, training, tournament experience, computer analysis and one of the best learning environments on the planet (he was already playing in the Marshall Chess Club at age 10).
Chess is similar to languages in that if you gain fluency at a younger age, you will not have an "accent" - you will flow in and out of this language like a native speaker.
This is Naka's current chess situation.
31 years of dedication (he's now 36 years old) while still being relatively young - this makes him look very impressive to those who have only put in a portion of the time and effort.
Reminds me of the piano maestro who was once having her play admired by an onlooker.
When she finished the onlooker said "OMG I would do ANYTHING to play like you do".
To which the maestro responded "No you wouldn't."
The maestro was right.