Can I tenderize my chicken before I vacuum seal it
This question is similar to better to marinate in vacuum? but is not a duplicate as the other question is very specific about how the chicken is to be used and this is more of a 'general' question. 

This is actually (IMHO) a 'very good' idea, especially if you plan to freeze these cuts in order to use later. Marinating is a 'surface process', it does not deeply penetrate the meat. Tenderizing significantly increases the surface area thereby increasing the contact with the marinade. Freezing continues this by disrupting the cell walls of the meat, again improving surface area contact. As it thaws the marinade will continue to coat the meat and improve the flavor, you would not need to thaw and then marinade. 

I would caution against using a strong alcohol in your marinade (say, stronger than beer or wine) as it may not actually freeze and it could also inhibit the freezing of the breast where it is contact, causing freezing to not preserve the meat as well. Whatever you use, try to freeze some of it first, just to make sure.