I understand you're looking for in full Spanish for PC. However, I must provide important clarification upfront: Halo 4 was never officially released as a standalone PC game by Microsoft or 343 Industries.
Would you like help finding the best current price for MCC or configuring Spanish language settings once installed?
If budget is an issue, wishlist MCC on Steam and wait for a discount (frequent 50-75% off). Avoid sketchy download sites promising "Halo 4 PC full español" – they are almost certainly malicious.