This is a counter, which usually means on'yomi readings from the kanji. Since 人 has two on'yomi readings, here's a mnemonic to help you remember which one to use:
Just think of the sheer number of people at Nintendo (にん). It must be huge. This really is just a counter for people that work at Nintendo.
There were 10 people, altogether.
How many workers are in Tofugu?
I have three children.