I suppose if they want to play it tactically they could but if they like Jack, why would they? Some probably won't nominate him because he selflessly turned down the beamer to save his, sorry their £150 grand prize. The worst case scenario is, if they think he's so popular with the viewers that nominating him, will make them unpopular.
I suppose if he is up early on, he might get overconfident and save his 3 immunities for later.