EXCLUSIVE: Christopher Nolan, it’s your turn up at bat. The DGA boss and his union are now the final major Hollywood guild not to make a deal with the studios and streamers, as SAG -AFTRA and the AMPTP today have reached an agreement on a new contract, we hear. No one has made it official yet, but after a week-long second round of talks, the Sean Astin-led actors’ guild and the Greg Hessinger-run organization have come to a bigger and cash-injected deal. Specifically, SAG-AFTRA has joined the ranks of the WGA and now signed a full four-year contract with the Alliance of Motion Picture and Television Producers. Additionally, labor sources tell us, SAG-AFTRA has received a “sizable” contribution to its pension fund from the AMPTP. This follows the WGA also agreeing to an extended-length contract with the studios and streamers last month in its own negotiations, as well as accepting a multi-million contribution to its ailing healthcare plan.…