If you tapped to the beats, but the beats are off just a little bit there are a few ways to fix it.
1. Retap, and close your eyes and be a little faster. The tap doesn't record when your finger hits the key, it records when the key is pressed down far enough on the keyboard.
2. Open the text file with excel or google sheets. Create a new column and have excel do the math for you.
You'll have a new column with new offset times. Save and import that.
3. Cheat and add .04 seconds of blank time to the beginning of your song. Or cut time as needed.
4. Forget XL tap and create new timing marks based on the wave form display in NC
5. Have audacity do the timing marks for you. Use the Bar and Beat Tracker: Beat Count plugin. It's very accurate.