Is employer paid tuition taxable income in PA?

Maybe. Any amount of reimbursement  over $5250, was (usually) already included in box 1 of your W-2, so don't duplicate that.

From the form PA-40 instructions:

LINE 1a, GROSS COMPENSATION
Income items that are always taxable as compensation include:

-Tuition assistance or educational benefits unless
the training or education is either 1) required by
law or regulation; or 2) required of the employee
by the employer in order for the employee to retain the skills necessary for his/her present
position. If the course, degree program or training is designed to enable the employee to enter
a new field or profession or to obtain a promotion, the reimbursement is taxable

https://www.revenue.pa.gov/FormsandPublications/FormsforIndividuals/PIT/Documents/dfo-02.pdf