Smith finished with 22 points, while Nolan contributed 20 plus 11 rebounds as Detroit went ahead 2-1 in the best-of-five series.
Detroit shot just 43.6 percent from the field but the Shock's defense limited Phoenix to 34.7 percent shooting and just 16.1 percent from beyond the arc.
Diana Taurasi scored 22 points and Tangela Smith recorded a double-double with 17 points and 12 rebounds. Penny Taylor also notched a double-double with 16 points and 14 rebounds, as she and Smith grabbed 26 of Phoenix's 47 rebounds.
Detroit has the opportunity to capture its second straight WNBA championship Thursday in Phoenix.