Yup, Mashita is a genuine family name. Two kanji "Ma" has many meanings, but probably in a family name, it means "rice field" And "shita" means "below". So probably Nick's family name means "below the rice field".

"Tak" doesn't exist as a Japanese name. You could have had Taka, Taku, or best of all, Take (means bamboo).

Bizarrely, and I'm not inventing this, there is a BBC sports correspondent called Nick Mashita.