CS for All initiatives have grown around the country, aiming to help build a technologically skilled workforce, increase diversity in the CS field, and provide students with the computing skills needed to be successful. However, we do not currently have enough educators to meet the swelling demand for CS instruction across grade levels. Further, schools of education are not offering sufficient CS courses to prepare new teachers in anywhere near the volume required. To address this gap, many districts are providing in-service professional development to build teachers' capacity to deliver high-quality CS instruction at scale. This paper presents findings from one large urban district's capacity-building efforts, which have consisted of a variety of in-service professional development (PD) opportunities, along with follow-up school support visits (SSVs) that include coaching and the use of a teacher-learner-observer (TLO) model. Specifically, we explore the influence of the SSVs on teacher's confidence in their ability to provide equitable, high-quality CS instruction. These findings contribute to our understanding of effective strategies to build teachers? capacity at the scale that is necessary to accomplish the goals of CS for All.