If you rolled over the 401(k) distribution to a Traditional IRA then there was not a taxable event.

Did the Form 1099-R you received have a code G in box 7 of the form?  Or did you indicate that you moved the money to another tax deferred account after entering the Form 1099-R?

Look at your tax return, Form 1040 on Line 4d.  If the amount distributed was rolled over then there will be a 0 entered in box 4d and on Line 4d the word ROLLOVER will be entered on that line.

You can view your Form 1040 at any time. Click on Tax Tools on the left side of the screen. Click on Tools. Click on View Tax Summary. Click on Preview my 1040 on the left side of the screen.

Does any amount appear in box 4 or box 12 of the Form 1099-R?  If so, unless you used other funds to replace these amounts to complete the rollover of the entire gross amount distributed from the 401(k), these amounts were not rolled over and are subject to income tax and potential early-distribution penalty.