Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you:

You have to remember the ちか portion to be able to read this word. Imagine someone close to you... Too close. They are so close to you that they're touching their cheek (ちか) to your cheek. Feel the cheek on yours, it's getting awkward.