Is canned wet food bad for kittens?

We just rescued a kitten that was trapped in my best friend's garage for several days. I took her to the groomers (to be cleaned and given a flea bath, if she had fleas, which she did not) and she was also at the vet yesterday. She's very thin, but other than being malnourished and having an upper respiratory infection (which we got meds for), she's very healthy. She was tested for feline leukemia and feline AIDs; both were negative. But she only weighs about 2.14 pounds and the vet said she should weigh about 4 pounds for her approx. age, which can't be more than 12 or 14 weeks. So our Vet said to let her eat as much as she wants because she needs to get some weight on. I got her some kitten chow and she's been eating that and also getting into our other cat's food. But would canned wet food help her gain some weight better? Or will that upset her belly? She is the sweetest little tortoise shell kitten and she's such a loveable little peanut.