Grate the onion and add the grated onion and its juice to the Instant Pot. Add chicken, BBQ sauce, worcestershire sauce, paprika and broth, then stir to combine.
Secure the lid, making sure the vent is closed.
Using the display panel select the MANUAL function*. Use the +/- keys and program the Instant Pot for 5 minutes.
When the time is up, let the pressure naturally release for 10 minutes, then quick-release the remaining pressure.
Shred the chicken, and divide amongst the tortillas.
Top with shredded red cabbage and serve with lime wedges.