This is a jukugo word, which usually means on'yomi readings from the kanji. Since 人 and 気 both have two on'yomi readings, here's a mnemonic to help you:
You're so popular that you've been given the Nintendo key (にんき). That's right, Nintendo gave you the master key to their entire office. Just like that.
This is a lot of responsibility even for your levels of popularity, so be careful not to lose this key!
This beer is very popular.
I am probing into why that doujinshi is so popular.
"I am the most popular berry collector around here," said the bear.