Restaurant-style Mexican food just got a while lot easier. And while your slow cooker won't serve up icy margaritas like the restaurant wait staff, it manages to do everything else to get South-of-the-Border flavor to the table while you get to kick back and relax.
Line a 3 1/2- or 4-quart slow cooker with a disposable liner. In a medium bowl combine the next six ingredients (through cumin). Spread 1/3 cup salsa verde in the bottom of the prepared cooker. Layer 2 1/2 of the tostada shells over the salsa, breaking to fit. Top with half of the chicken mixture. Spread 1/3 cup salsa over the chicken mixture. Top with 1/3 cup cheese. Repeat layers once. Top with the remaining tostada shells and salsa.
Cover and cook on low for 3 hours, rotating the crockery liner halfway after 1 1/2 hours if possible. Turn off the slow cooker. Top with the remaining 1/3 cup cheese. Cover and let stand 15 minutes. Top servings with remaining cilantro, queso fresco, and a drizzle of crema.