Yes. There is no better way to marinate chicken than to defrost it before having it marinated. Here, you will be spared all of the cons that come with marinating a frozen chicken. This is because the absence of frozen crystals on an already defrosted chicken will aid easy penetration of the marinade into the pores and fibers of the chicken, such that it juices up easily and soaks up in the flavors therein as intended for it to be.