Do you doubt that Palin will be the nominee?

[Ⓐnarchy in the ☭☭☭P!]

How is she going to do that?

First of all, this assumes she runs (right now, her position as Conservative Kingmaker is quite pleasant for her, running for president might trash that and ruin her influence later). If she runs, it will probably be in 2016.

Second, this assumes she has a strong enough base. Yes, she has some tea-party support. No, this does not translate to her winning on a "Tea Party Platform". The fact of the matter is, a large portion of the party could easily be swayed to someone else. The Social Cons she might pick up, but Huckabee will probably grab a lot of them if he runs, and if not she will still be running on a rather limited platform (A small portion of a small portion of the Republican Party). The Fiscal Cons will probably prefer someone who is more concerned with their issues, meaning someone like, say, Ron Paul or Gary Johnson or whoever the equivalent is. She definitely won't be picked up moderates due to her rather unfortunate combination of views that narrows her support base quite a bit (Social Conservative, slightly Fiscal Conservative but not enough to sway the FC vote, anti-liberal, etc).

Third, she is loaded with the baggage of being considered an "idiot" from the 2008 race, when she said some very cringeworthy things. As much of a terrible president as I think Romney would make, I cannot quite honestly say he is an idiot. Palin, on the other hand, makes me wonder. I guarantee there would be a sizable portion of the Republican Party that would choose Stalin over Palin.

She will either support someone else and try to play kingmaker, or she will run, do poorly early on, and drop out.

[Ⓐnarchy in the ☭☭☭P!]

yes: she'll start off with several huge advantages, there's no way she can survive a year-long primary campaign without alienating supporters and making critical gaffes, especially since she won't be the only Far Right/Tea Party candidate. It will be an extremely nasty primary fight though.

Bingo. She is far too prone to gaffes and stupidity too do well. She is guaranteed to kill herself early on because the MSM won't be tossing softballs at her and she has the opposite reaction to how the media throws hardballs that Obama does (As much as I dislike Obama, he always has the best reactions for hard questions). Some other Tea Party candidate will trash her.