I want to change my job while my PR application is still getting processed by the ICA. Will this affect my chances of approval?

Switching your job during your PR application does not usually negatively affect you unless you are frequently switching jobs. Getting a promotion or increment is always a positive change.

However, do inform ICA about this change. In addition to that, every time there is a crucial or huge change in your profile after submitting your application, such as adopting a kid or a newborn, you must inform Ica with the relevant documents.