That depends very much on what kind of side chain implementation you are looking for. If you want something like assets on one chain being locked under a multisignature, and then being reissued on another chain by those parties that signed the multisignature, and then at some point being exchanged back for the asset on the original chain - then yes it's absolutely possible.
But if you're looking for the kind of side chain where one blockchain directly verifies data taken from another blockchain in order to release assets, then this is not supported directly by MultiChain. Although you could implement this kind of logic using a transaction filter in MultiChain 2.0, if you coded it yourself.