The Native American Astronomy Outreach Program (NAAOP) at Lowell Observatory is an in-class STEM enrichment program that pairs astronomers with 4th-8th grade teachers at Native-serving schools in northern Arizona. The astronomer works with the teacher to present hands-on astronomy activities to their class with the goal of getting students excited about STEM and STEM careers. Over three school years (2018-2021), a special collaboration with teachers at the Navajo Nation's Kayenta Unified School District was used to develop and implement curriculum units for each grade level with potential for a high impact on students. The curriculum used Project Based Learning to better enable students to see themselves as scientists, and it included cultural and local connections related to the science content to encourage students to see science as relevant to themselves. Although impacted by the COVID-19 pandemic, student surveys suggest that these curriculum units along with the other components of the program had a positive impact on students' interest in STEM.