Nephi didn't realize it but the Lord was getting ready to give him the power over the very elements and crush the wickedness right out of this whole abominable segment of humanity, both Nephites and Lamanites. But it was not to be right away. The Lord said he was willing to give this priesthood power to Nephi because he knew Nephi would never use it until he was commanded to do so by the Lord.
Just so Nephi would know how much power the Lord was putting into his hands he itemized the extent of the power Nephi would ultimately be allowed to exercise.