it wouldn't start and the security light kept flashing. I finally got it to quit flashing but it still won't start. I checked fuses and swapped the anti theft relay with the wiper relay. Still no luck. The light started flashing again. I got it to stop again. But still no luck starting. Battery is good lights come on. I hear the ignition click but it won't turn over. But it doesn't sound like the starter clicking. Any ideas out there? Thank you

Sounds like it still may be alarm related.
However, If the clicking is at the Starter and it doesn't turn over, it may be the Starter?
When I do Security on Vehicles, I like it to shut down Starter, Ignition, and Fuel?
See if you can find Exact procedure for Resetting Alarm.

It's typical for the security light on Nissans to flash, if the battery gets low or you have removed the battery cables. I suspect the battery is bad--have it charged or replaced. Be sure to clean the battery terminals and cable connections. Afterwards, have the alternator checked. The security light should stop flashing, once you drive the car for a little while.

If the starter motor doesn't turn, but the starter solenoid (relay) "clicks" when the ignition switch is turned to Start, the problem is with the battery, starter solenoid, or starter motor connections. Remember, you need a minimum of 12.4 volts across the battery terminals for the starter to work.

In order to check the solenoid, perform an Ignition By-pass Test, by placing the transmission in Park, engaging the parking brake, removing the push-on connector from the solenoid “S” terminal, and connecting a jumper lead (12 AWG), or preferably a remote starter switch, between the B+ terminal on the solenoid (or positive battery terminal) and the exposed “S” terminal on the solenoid. If the starter motor now operates, the solenoid is fine and the problem is with the starter relay, ignition switch, neutral safety switch or clutch interlock switch, fuse, fusible link, security system, or wiring. If the starter motor still does not operate, replace the solenoid.