Place shredded chicken in a medium saucepan and combine it with the Morelos sauce and heavy cream. Cook, over medium heat, until the chicken is moist but not juicy, about 5 minutes. Season to taste.
To assemble the tostadas: Spread refried beans on a tostada, add the chicken mixture, top with shredded lettuce, avocado slices, crumbled cheese and some cream. Provecho!