After swapping battery and USB port, Nexus still won't charge!

I've scoured the internet in search of my specific problem, but can't find the question (or answer). I consider myself quite handy with electronics.

The Nexus would have trouble charging until I wiggled the cable into the exact location, eventually, it stopped charging at all. I let it sit for months...

I eventually decided I wanted all my games back, so I tested my theory by buying a new replacement battery from amazon. I swapped batteries, and instant life returned to my Nexus. There was a partial charge on the new battery. However, after plugging in with various cables and the OEM AC adapter, the battery eventually faded to dead.

I installed two different replacement USB/headphone ports with no luck. I reseated all the cables everywhere and can't figure anything out. The 4-pin charger dock is expensive, so I'd like to avoid that.

If it helps at all, the screen had the occasional ghost-touches, like the digitizer was damaged, but after putting in the factory charged battery, it still came to life with no issues....Thoughts?

Holding down any of the three buttons does nothing btw.