(Nielsen is famous for an over-exaggerated third strike call in Naked Gun.)
There are three distinct strike calls in the video and although they are tough to decipher, these seem right:
Strikeout No. 1: "2 Chainz."
Strikeout No. 2: "He got Gangham Style."
Strikeout No. 3: "And he closes the show like the champ that he is."
An umpire yelling, "2 Chainz"? My life has been made.— Adam Bernstorf (@IDoNotGiveAdam) July 22, 2014
My umpire today was rapping 2 chainz behind the plate— Preston Bowling (@THElegendbo22) April 29, 2013