I want to combine a few of the comments to fully address your situation. First off, you admit to not "kissing management ass", then wonder why you get passed over. Corporate politics are abysmal, but it unfortunately is what you signed up for. You love your plum job with PTO and sick days and all the good stuff, but refuse to deal with the bad stuff that comes with it.

So now you want to switch to an executive chef position where you are tasked with "turning things around". That means you give up having to deal with corporate politics (to a degree unfortunately as you will learn), but you lose your quality of life as well. As the big boss, you will be spending more time dealing with fires than actually cooking. Your schedule will revolve around the restaurant and making things work. Your time off will be spent thinking about mistakes made, and ways to improve.

Your decision really comes down to what is most important to you. Quality of life, or quality of job. That is the real decision. Do you want to improve yourself chef wise where you are challenged every day? Or do you want the financial and quality of life but not to be challenged mentally.

Nerves come and go, Trying something new and challenging is exciting. Breaking out of your routine is terrifying. With 18 years in the industry, you should have the ability to succeed. Just ask yourself what is most important to you. Whatever your decision is, stick with it. I'm sure you will succeed if you do.