Hi Rachel!
What was the issue before you replaced the battery?
Could be a lot of things causing this. Where did you got the replacement battery from? It's possible that the new battery accidentally damaged the motherboard.
Could be the following IC's which are failing:
* Maxim Integrated MAX77620HEWJ power management IC
* Rohm [link|https://www.rohm.com/products/interface/usb-type-c-power-delivery/controller/bm92t10mwv-product|BM92T10MWV-Z|new_window=true] USB-C power delivery controller
* Texas Instruments [link|http://www.ti.com/product/BQ24193|BQ24193|new_window=true] battery charge management
* Maxim Integrated [link|https://www.maximintegrated.com/en/products/power/battery-management/MAX17050.html|MAX17050|new_window=true] battery fuel gauge
Please check those IC's or let them be checked.
Hopefully you will get the Switch working again.