In a medium saucepan bring broth to a boil. Add lentils and simmer until lentils are tender but not falling apart, about 20 minutes. Drain, reserving the liquid.
Cook the fettuccini according to package directions. Drain and keep warm.
Purée basil in a blender or food processor and set aside.
In a large skillet over medium heat, cook garlic in oil until golden brown. Add bell pepper and olives and cook until peppers are soft. Add wine and simmer 30 seconds.
Stir in butter, chicken, basil purée, lentils, reserved liquid, salt, and pepper. Bring to a simmer, cover, and cook until the chicken has lost all traces of pink.
To serve, transfer the fettuccini to a warm serving bowl and top it with the lentil-chicken mixture.