I am not a fan of Chows as every one I met was aggressive. that said, I am on my 3rd chow/lab mix. You just never know with a mixed breed which traits are going to come through.
The first one was The. Best. Dog. Ever. He was a beast of a dog with a huge head and people were intimidated by him. However, he was the sweetest, most lovable, affectionate, gentle, docile, well behaved kid-loving dog I've ever known. He would snuggle up with my nephew to keep him warm when we'd take him camping up in the mountains.:001_wub:
We loved him so much that when we saw some adorable chow/lab puppies being given away we got another. She was also very sweet and affectionate. To me. She didn't like most other people and hated children. We had to get rid of her when my daughter became mobile because she would follow her around growling and would sometimes lunge at her face.
Last spring we got another chow/lab puppy. She's not as calm as our first (but we got him when he was a year, so he may have been a super-hyper pup as well) but is very friendly and loves people, especially kids.
Good luck!