Source of translations: Nguyễn Ngọc Huyền Minh twitter

Sibyl said:

Nguyễn Ngọc Huyền Minh

...is Nguyen like Smith but for... Vietnamese?

FRien said:

...is Nguyen like Smith but for... Vietnamese?

Most common surname for Vietnamese people, yes.

NNescio said:

Most common surname for Vietnamese people, yes.

...neat. Do you pronounce is as it looks?

FRien said:

...neat. Do you pronounce is as it looks?

Yes.
Vietnamese is a language spoken how it's written these days.
That's how the writing system was created after all.

FRien said:

...is Nguyen like Smith but for... Vietnamese?

Nguyen is an absurdly popular last name in Vietnam (My last name is Nguyen.)
Around 30-39% of Vietnamese people have the last name Nguyen.