Question

what does the code P1110 mean for a 1998 Nissan 200SX 1.6 liter engine mean?

Answer 1

most likely the Intake valve timing control solenoid valve is stuck or something. When was the last time you replaced your oil? if it was more than 3700 miles ago you might want to replace it again 

Since the Intake valve timing control solenoid valve uses oil flow to control timing, dirty oil can cause the valve to stuck open or close. Before replacing the valve, change engine oil and filter and reset engine code.
 

You can also do an oil flush, which I have seen help.