Here's the recipe from Not Your Mother's Slow Cooker Recipes for Two
Cooker: 1 1/2 to 3 quart crock pot
Setting and cook time: High for 2 1/2 to 3 hours
2 boneless, skinless chicken breast halves, trimmed of fat
Salt and freshly ground black pepper to taste
1 cup plain Alfredo sauce
3 to 4 tablespoons Pesto Sauce
Spray the inside of the crock with nonstick cooking spray, and arrange the chicken breasts in the slow cooker. Sprinkle with salt and pepper. In a small bowl, combine the Alfredo sauce and the pesto sauce; stir to combine, then pour over the chicken. Cover and cook on high for 2 1/2 to 3 hours, until the chicken is tender and cooked through. The chicken will make its own juice and thin the sauce. Serve hot.
In place of pesto you could try:
Chicken with Lemon Cream Sauce and Olives: Add 6 to 8 whole black olives (canned or kalamata in brine) and the zest of 1 lemon to the Alfredo sauce.
Chicken with Chipotle Cream Sauce: Add 1 to 1 1/2 tablespoons chipotle paste or 1/2 mashed chipotle chile and 2 teaspoons of adobe sauce to the Alfredo sauce.
Chicken with Artichoke Cream Sauce: Add 2/3 cup of drained canned or thawed frozen artichoke hearts to the Alfredo sauce.
Chicken with Curry Cream Sauce: Add 1/2 teaspoon of your favorite mild or hot curry powder and 1/2 teaspoon fresh grated ginger to the Alfredo sauce.