First I'd recommend planning a strategy with your marine friend about what each of your armies should do. Vanilla marines have access to alot of heavy weaponry to kill armored vehicles and heavily armored infantry at range.
Just a few general suggestions would be biovores with poison mines - they will kill most eldar aspect warriors and vehicles (the open topped ones) and have a reasonable chance of wounding nurgle marines/daemons.
Try to handle the assault portion of the battle. Tyranids can generally throw out better assault units than a marine army can. A standard 'nid list will help here with a mix of CC gaunts and some rending claw creatures. It's hard to be more specific without knowing what units you might be facing.
