Does a Secretary of State have the power to certify the election results of another state?
Each state has its own constitution and no state holds power over another, so one state's Secretary of State does not have authority to certify another state’s election results.
According to Democracy Docket, "The certification of election results is conducted at the state level, either by a state board of elections or the state’s chief elections officer (in 47 states, that’s the secretary of state)." In Arizona, it is the Secretary of State’s duty. Secretary of State Katie Hobbs did not need to resign to run for governor. Hobbs is in her final year of office, so she was not required to resign before running for governor.
Georgia's current governor, Republican Brian Kemp resigned as Secretary of State before his office certified his election results in 2018. His replacement was appointed by then-Governor Nathan Deal.