Joe Simpson's quite a forgiving guy ... 'cause Jessica's dad tells TMZ he would still have a beer with Nick Lachey ... even after his daughter's ex-hubby TRASHED him on national television.
It was just last month that Nick went on "Watch What Happens Live" and told Andy Cohen ... the best part of divorcing Jessica was not having to play grab ass under the table w/ Joe at family events.
But Joe -- who hit up Greystone Manor with 3 pretty hot chicks this weekend -- told us he still "loves" Nick after the diss ... and praised him for being a good husband to his daughter.
Sidenote -- at one point in the video, Joe's hot friend in the pink dress addresses the gay rumors ... even though nobody really asked her. So, check that out.