Thought this would be an interesting battle. Anyway, 3 scenarios:
Scenario 1: Original Team vs Chitauri
Scenario 2: New Team vs Chitauri
Scenario 3: Original and New Team working together vs Chitauri
These are the animated versions, and Loki is at the power level he was in Thor only in the third scenario. Bloodlusted, morals off. Can they stop the invasion?
Edit: In all 3 scenarios the team has 1 day of prep.