I'm not a Japanese specialist, but I'll try to explain. FYI:[チャレンジし(try)/たい(want to)/から(because)] チャレンジし is originally a verb "チャレンジする", but when combined with たい, the form is changed into チャレンジし.I'm wondering if you can find such word as なぜなら, だって, each of which has the meaning of "because"(なぜなら～から, だって～から). So I would conclude that チャレンジしたいから is translated into "Because I want to try".