In a nonstick skillet, toast the pecans over medium heat, tossing frequently, for 2 to 3 minutes. Transfer the nuts to a bowl.
Season the chicken with salt. In the nonstick skillet, heat the 2 tablespoons of olive oil over medium heat and cook the chicken pieces, stirring occasionally, until just cooked through, about 5 minutes.
Meanwhile, in a blender, combine the remaining 1/3 cup of olive oil with the basil, lemon zest, lemon juice and 1/3 cup of the pecans and blend until smooth; season the pesto dressing to taste with salt.
In a medium bowl, toss the cooked chicken, pears and the remaining toasted pecans with half of the dressing. In a large bowl, toss the salad greens with the remaining dressing. Divide the greens among 4 plates and top with the pecan-chicken mixture.