The Godly can definitely influence ungodly political leaders1,2,3,4,5,6,7. In most cases, we don’t know of the personal influence they may have had on the leader1,3,4,5,6,7 but we are told of the policy influence1,2,3,4,5,6. In at least one case, we can see the influence and effect they had on the leader personally2.
In all cases, we confidently know through Scripture’s testimony the righteousness of the influencer. God was at work through the pure hearts of Joseph1, Daniel2,3, Ezra5, Esther4, Nehemiah6, and Paul7.
Conversely, we don’t know the spiritual condition and state of those they influenced. Did they turn their hearts in the end? We don’t know, and like today, we won’t know until that Day. But, it’s not implausible to think that the great Nebuchadnezzar himself awaits us in heaven2. Wouldn’t that be something?