A “spiritual nerd” is someone who is narrow-minded spiritually, and who lacks common sense. They can’t rationalize between what is truth and what is formula. A “nerd” will only work in one way – through formulas. If you don’t have a formula or an equation to figure something out, it is not real. Factual evidence is needed to believe in something spiritual.
The Pharisees were much like this. They knew all the prophecies and the scriptures, but didn’t recognize the Messiah when He was right in front of them. Today, we cannot afford to be spiritual nerds, or like the Pharisees of Jesus’s day. It is not enough to just know the scriptures, you must also know God’s heart behind them, or what He meant by them. We cannot assume anything, or we will wind up with God’s judgment.