Take a large saucepan and melt butter in it over low heat.
Add garlic to it and let it cook for 30 seconds.
Now, add tomatoes and ¾ cup of the chicken to it.
Keep it on medium heat and let it boil.
After boiling, reduce heat and simmer it uncovered for about 10 minutes until they get softened.
Now, add the cream to it and again bring it to boil. Stir it as well.
Simmer over medium heat for sauce to get dense and thick.
Season the chicken with salt and pepper from both sides.
Take a large griddle and heat oil in it. Cook chicken in it over medium heat.
Make sure to press on the chicken with a slotted spatula in regular intervals while cooking (every 4 minutes).
It is advisable to cook it from both sides thoroughly or until the meat gets whippy and no amount of pink remains inside .
After transferring it to a board, cover it and ensure it remains warm.
Now, the fat should be discarded from the griddle.
Now, bring 1/4 cup chicken broth to boil in the same griddle, along with stirring pan juices.
Slightly, reduce the heat and add cream sauce to it.
For taste, add basil and other seasonings.
In the meantime, take a large pot. After adding slightly salted water to it, bring it to boil.
Then, put fettuccine in it and cook for around 10 minutes.
Drain it and transfer the pasta to a bowl. Finally, toss it with 4 tablespoons sauce.
Each chicken breast is to be cut into 2-3 diagonal slices.
Now, serve the pasta topped with chicken and the cream sauce.