I was just wondering if I can arrange raw chicken on the pizza base and cook everything along or if I should cook the chicken first separately.
Cook the chicken ahead of time. I doubt your pizza cooking time and your chicken cooking time will be a perfect match, and it is more likely than anything that your chicken would be undercooked. That would not be good for anyone.
If you are worried about the chicken being dry on your pizza, you can try par-cooking the pieces instead of fully cooking them (though that may be a little dangerous, too), or you can add the cooked pieces to the pizza after it has begun baking.
I've a bias against putting raw chicken on anything that possibly might not get thoroughly cooked. It has something to do with Salmonella. That said, the high percentage of water released when cooking poultry, as opposed to other meats, might cause your pizza crust to become soggy, or your sauce liquidy. Neither of these are good things when it comes to pizza.
i put the chicken on raw. I cut it thin and in small pieces so that it cooks at 450f for about 15 minutes. The trick is to cut it when its still a little bit frozen it is much easier this way. The chicken cooks perfectly and is not burnt, fried, not dry. People are so scared of raw chicken its hilarious. I cook my chicken, mushroom, and onion pizza RAW.