The immortality isn't combat-applicable.
Jesus typical starts with a mix of his guns, telekinesis, while also flying around and evading attacks. Jesus regularly takes on hordes of people with guns, so Sans' Danmaku isn't completely unavoidable for him.
Sans' gravity manip, as well, is countered by Jesus' flight. It's more or less impossible to determine for sure if Sans' telekinesis is stronger than Jesus', however, Jesus has Class K, so it's likely that Jesus has the advantage there. (Without any feats, you really can't assume someone has Class K.)
Sans spams Teleport more than Jesus, though Jesus is more likely to use his telekinesis to actually do damage (Jesus has used telekinesis to shove a person into a floor, or crush people with large objects) rather than simply pushing them into other attacks.
Sans has Soul Manip, but contrary to popular belief, it is not a one-shot ability.
So, let's go down to AP. Sans scales from Frisk, who was untouched by 60 MJ. Jesus regularly vaporizes people (300 MJ) and fights people comparable to that, likely with a tad bit of upscaling. Jesus likely has the advantage in AP, Sans largely upscales from 60 MJ, but Jesus is around 300 MJ, which is five times more than 60 Megajoules.
All together, I'm going to give this to Jesus. Jesus' forcefields, flight, and experience with tons of bullets from all angels should help him avoid the bones, and the Soul Manip isn't a one-shot, so he can afford to be hit a few times. With his own Telekinesis, he can beat up Sans from afar. Sans can try to dodge, but Bullettime and Telekinesis make it very difficult.
As well, Jesus has an overall skill and AP advantage, meaning he could probably take Sans out quite quickly if it came down to it. Not to mention, Sans is very likely to get tired if the fight takes too long, while Jesus will just keep on fighting.
Due to Jesus' AP, skill, reaction/speed amp, and abilities to counter Sans' danmaku, I vote Jesus.
