Your machinist makes some sense but there are questions:
What year 302?
What will be the primary role of the finished car?
What's your budget?
Fuel injected?
What parts do you already have?
What do you already know that you need to buy?
I'm not a fan of having nitrous as the only power adder. I would rebuild the motor with the stock nodular crank with forged rods and pistons. I would select a cam that runs well N/A but is well suited for adding a super-charger later. Aluminum heads are a "must-have". There's lots to choose from and out-of-the-box, the differences are more about "when" power is greatest and less about "how much". I would stick with shorty headers, a good H-pipe with 3-way cats, and stainless cat-back. This should net 260+ without issue.
If it's a 5-speed, I'd swap the fly-wheel for forged steel and look into having the T5 re-worked by a transmission speed-shop. Auto - still needs to be re-worked.
Next, I'd drop the family fortune on brakes and
suspension. This will cost between $2k and sleeping in your car.
Of course, this is all based on what "I" would want out the car. Tell us about what you want out of it.
It still blows my mind to see one of these cars making sub-300 RWHP with a kick-ass
suspension. I take particular joy in watching them pass BMWs and Porches on a road course.
Them: Damned cheap-ass Pony car.
Oh... and welcome aboard!