Glad to hear if Rob.

You did not say what is happening only that it is not working.
I took a look at your code and several things jump out at me.

1. You are jumping into the deep end of the pool with testing "nap"
If would take a smaller step first. Set a flag in the ISR and resume. Then in the main act on the flag you set in the ISR.
This way you can see the effects of the ISR logic.
2. You have IOC.1 enabled, which is GP1, which you are using for the comparator. You need to comment out IOC.1.
3. You are not testing for which Interrupt is firing inside of your ISR. It is almost always a good practice to determine what interrupt caused the jump to the ISR.
4. At the end of your ISR you are not setting the INTCON register they way you think. I believe you have a typo in the value you are assigning to it.


I changed your code to the following which shows the changes.

Code:
'PIC 12F683

#CONFIG 
   __config _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _CP_OFF
#ENDCONFIG

PAUSE 20 'wait for hardware to settle

DEFINE OSC 4 '4mhz ocsillator
ANSEL = %00000010 'pin 6 analog
CMCON0 = %00000100 'comparator mode
VRCON = %10101000 'voltage reference
TRISIO = %00000010 'pin 6 input

ON INTERRUPT GOTO SLSELECT 'interrupt handler is slselect
INTCON = %11001000 'enable GIE and GPIE; clear GPIF
'IOC = %00000010 ' enable IOC1 (GPIO.1 Interrupt on change)
PIE1 = %00001000 'enable comparator interrupt

POT1 VAR CMCON0.6 'read potentiometer
LED VAR GPIO.2 'led pin 5

bitTest var bit 'Debug test bit.  Set/Clear in ISR and Check in maiin

bitTest = 0

ENABLE
main:
    
    'HIGH LED 'light led
    LED = bitTest
    
GOTO main 'repeat

DISABLE 'disable interrupts in handler
SLSELECT:
    'IF POT1 = 1 THEN 'if <1.1v sleep
        'NAP 1
    'ELSE
    'ENDIF
    if PIR1.3 = 1 then  'Comparator Interrupt fired (must be cleared before resume)
        bitTest = POT1
    endif

    'INTCON = %10001000  'enable GIE and GPIE; clear GPIF
    INTCON =%11001000 
    PIR1 = %00000000 'reset CMIF
    RESUME 'where left off
    ENABLE 'enable interrupts
See if this gets you along further.