How Many Lights Can Go On A 15 Amp Circuit Breaker?

For 15 amps:

Lets suppose that all your lights are 60W:

120Volts * 15Amps = 1800 Watts;
so from there a regular 15 amps circuits has 1800W to spare therefore:

1800/60 = 30 lights at 60 W each, or 1800/100= 18 lights at 100 Watts.

The current NEC allows a maximum of 12 devices on each 15 amp circuit.
So that is 12 receptacles, and/or lights.
As a practice, we usually arrange circuits into two types:  Receptacle circuits, and lighting circuits.  But that isn't a requirement, just our local convention.

Also, in the kitchens, we typically run only 20 amp circuits (with 12 gauge wire, not 14-gauge!)
And to be safe, we have separate circuits for:
- refrig
- microwave
- dishwasher
- disposal
- half of the receptacles (with a GFI device in the first location)
- ditto for the other half of the receptacles

To make it safe, just use 80% of the total wattage you can take from amperage * voltage

so if you have....
A power of 120 V
120 volts * 15 amp = 1800 watts
80% of 1800 watts = 1440 watts

a power of 240 V
240 volts * 15 amp = 3600 watts
80% of 2400 watts = 2880 watts

Depends on the wattage and how many will be on at one time, it would take a lot of lights to trip a
15 amp breaker.