The game's lone run came in the fourth inning when Eric Hosmer hit an infield single to score Mike Moustakas.
Detroit starter Anibal Sanchez (7-11) pitched seven innings and gave up one run on seven hits.
Austin Jackson went 2-for-4 on the night, accounting for half of the Tigers' hits against Chen.
Kansas City's Greg Holland earned his ninth save of the season.
This pitching duel could hardly have been more different than the Royals' 9-8 win on Tuesday night in Game 1. The series will conclude with Game 3 on Thursday. First pitch is scheduled for 7:10 p.m. CT at Kauffman Stadium.