I made up a special rule for anyone who wants a little spice in their next playthrough. Here it is:
When you are in the room to select your starter, save the game, then check your Trainer Card. When you open up the Trainer Card menu, look at your ID Number in the top right, this will be the key factor in what starter you'll have in this run.
The first number will determine what type it'll be:
1-3 = Grass
4-6 = Fire
7-9 = Water
0 = Your choice
The next four numbers will determine what generation it's from (0 counts as an Even):
All Odd = Gen 1
All Even = Gen 2
2 Odds > 2 Evens (2 Odds add up to more than the Evens) = Gen 3
2 Evens > 2 Odds = Gen 4
3 Odds = Gen 5
3 Evens = Gen 6
In the event that 2 Odds and 2 Evens add up to the same number, you get to choose the Generation.
Example: If my ID Number is 23456, that means my type is Grass, and since the 2 Evens add up to be greater than the Odds, that means my Generation is 4. So my starter would be Turtwig!
Now, for the Faithful part...
Once you figure out what starter you're supposed to have, you HAVE to get that exact starter (you may soft reset as much as you want to get better IVs, Nature, and Ability, as long as you still get the proper starter).
You MUST use this Starter for the whole game, no switching it out of the party for something else (unless it's for something else that's not battling, like breeding or whatever).
You have to at least have your starter in your party (don't have to use them, they just have to be with you) in every battle you fight. And yes, EVERY battle.
One last rule that only applies to a Nuzlocke: Your starter will get 3 lives, refusing to die. But once that final life is gone, you have to release/permanently box it like normal.
And that's it, come back here and post what starter you get, and good luck!