Need to know if I can directly connect the OUT and IN pins on the explorer to the Rx and Tx pins on the Nano 33. Both are 3.3v and seems like it should work, just concerned that the pullups on the explorer level shifter will cause a problem. Any advice would be appreciated.
It should work; if not, try removing the pullup…you can always re-solder the pads 
Looks like it works well without cutting the pullups and hasn’t overloaded the Nano33 IOT I/O pins which are rated at 7ma.