You can't. You can only get it as a starter.
I have them in Heartgold
You won't need to use an Action Replay to get a Chikorita in SoulSilver. Chikorita is one of the starter Pokemon in the game. Though, if you started out with another starter Pokemon, then yes, you will need to use an Action Replay to get a Chikorita.
CHIKORITA!
It's a starter pokemon.
If you start off with Totodile, your rival will have the Chikorita evos.
Chikorita is a beginner Pokemon at the beginning of the game. you can choose either totodile,chikorita, or cyndaquil. that's the only way you can get chikorita or you can just trade one over to the game.
Unless you trade with your friends - Impossible!
The Starters are Cyndaquil, Totodile and Chikorita
toddile,chikorita and cyndaquil
i have one in soulsilver.
There is not a trainer in soul silver that has a chikorita.
If you´re talking about chikorita, there are two ways to get it: 1 - Talk to Prof. Elm in the beginning of the game and choose chikorita; 2 - Trade chikorita from another game or with another person.