"no bu5" dashboard msg after installing new oil sender switch

The message is "NO BUS". It refers to the Data Bus which all your computer modules use to speak to one another. This can be a very involved problem, it might be a problem with the bus harness itself, corroded or bad wiring, or a bad connector, or it might be a bad module, or a problem with a loose module. A lot of times it can be hard to pinpoint where the problem spot is and requires the dealership's scan tool to find, meaning it has to be taken to a dealership or well qualified shop to be fixed. But first, try some simple fixes: open up fuse box and reseat all fuses. Find where your engine computer (ECU) is and reseat it as well. (the ECU might be located under the fuse box, but Google it's location, I'm not that familiar with Mopars). Check over your wire harness, look for any trouble signs, brittle or chafed wiring, or loose harness connectors. Since you were working in the engine bay, check wiring in that location especially.

Thank you. I still feel it's related to swapping that sender out.

I don't think an oil sender alone can cause this message, it's almost always related to a wire harness, pins, or connector going bad. Have you tested the sender unit to see if it was actually bad? (You'll need a ohmmeter to test it, Google a "how to".) Check the TIPM (totally integrated power module) under the hood, a bad pin or ground there can affect sensors, I believe the TIPM is also the biggest cause for "no bus" conditions.