When getting a basking bulb, check the box for the word "equivalent." Many bulbs these days have something like "100 Watt" in big font and then in small font state "equivalent; only uses 15 watts" or something of the sort. So essentially you need to find something that actually uses 45 watts or 65 watts depending on ambient room temps. I'd probably go with a 65-watt bulb and hang it high up over your cage.
Oh, and the keyword is to find a bulb that is incandescent or a halogen. I'd reckon that none of the LEDs (in your local stores) will have enough watts to create significant heat. Though you can use grow lights or pool lights that are LEDs that get hot enough to be a Basking light, but those cost significantly more (but are a great investment because you can kill two birds with one stone by using the basking light as a grow light for your plants as well).
Additionally, after doing more research. I also cannot find the exact bulb that Neptune the Chameleon uses online. All the new eco-smart bulbs use less watts which makes sense if your basking spot only gets 65 degrees.
Since your cham will still be small and will easily be able to climb the screen top, you want to have your basking spot up higher in the cage, and then raise your bulbs even higher up off of the screen top, this way if your cham does climb the screen top, he/she won't get burned.
Also, if you live in California, it is getting harder to find good basking bulbs in hardware stores such as Home Depot or Lowe's. Lately, I haven't been able to find any there. But I did try target and the highest watt bulb I could find was a 45-watt bulb. This is due to California's bulb restriction of bulbs being 45 lumens per watt. One of my brightest incandescent bulbs is 65 watts at 580 Lumens. This is only 8.9 lumens per watt which is not even close to 45 lumens per watt requirement.
So if you are having a hard time getting a 65 watt incandescent, I might try going to a pet store and look for a reptile basking bulb that advertises daylight.
Let me know if you have any questions. I'm feeling loopy so I might not be making sense. I will gladly clarify if you have any questions.