Yes, of course. Any pokémon may raise any other, regardless of species or type of both the “parent” and the child. So long as your sandslash is careful, both it and your chikorita should be fine.
Is it safe for my Sandslash to be rearing my newly hatched Chikorita? I obtained the egg from a breeder so that i could have my first ‘real’ pokemon, since the Sandslash was my Dads who gave it to me. Sandslash is acting very motherly towards him, and I want to make sure that this is acceptable behaivior.
Published
The Pokédex According to Bill 