All major energy companies have Career/Jobs sections on their websites where you can create or submit resumes directly and apply for specific jobs.
As far as what makes you a better candidate...
1. Step 1 is getting invited to an interview. That hinges on your resume. Your resume should reflect professionalism, attention to detail, organizational skills, and conciseness. For your level of experience 1-2 pages is adequate. You will learn the finer points of resume building during TAP.
2. Step 2 is how you represent yourself on the phone. Eventually HR people will call you and how you come across verbally is very important. The old saying is that a person can hear a smile over the phone. Very true. You may have phone interviews with your perspective peers and superiors before being asked for a site visit. Again, be prepared with notes, answers to typical interview questions, and your own questions. Be prepared to engage your interviewers. I have developed a knack for turning an interview into me interviewing them. People love to talk about themselves and their jobs. Engage them.
3. Step 3 is the face time. Buy a suit and have it tailored for you. People in suits are treated better than those dressed casually. Like you I am a big guy and can not buy a suit off the rack at your local outlet. I had one made and tailored to fit my frame. Buy a suit that matches a variety of colored shirts. I prefer olive. I also like the cut of Brookes Brothers dress shirts. Get nice pair of leather shoes with a heel. A heel gives you a more professional posture. Don't skimp on the clothes or the shoes. A quality suit of clothes will last. Shine your shoes too. The first thing most men notice about other men are their shoes. You will be sized up bottom to top as you approach your interviewers. I like Kenneth Cole Reaction dress shoes.
Again, conduct yourself professionally comfortable, meaning...own your space. That can only come through being thoroughly prepared: Research, Questions, Answers, hard copies of your resume printed on quality bonded paper, and your outward appearance. Simple right?
It is if you start preparing now.
4. Now on to the jobs. This is open for debate, but nuclear power aint goin away any time soon. The future of energy is not without nuclear power, therefore I would stick to what you know. There are no shortages of Operator Jobs out there for nukes. The money is the best in the energy industry for new hires. You will make 50K plus from the get go in many places and the oppurtunity is there to go into the high 5 low six figure range with OT and if you pursue licensing.
5. Don't forget college. It may not be a requirement to be an NLO/AO, but it wouldn't hurt to get a degree.
Good luck.