Simply 3.d3 is probably best. After 3.Nc3, you occasionally get these pests who play 3...Nxe4. Or you can mix it up with 3.Qe2!?, which wins in all variations.....
2...Nxe4 Challenge excepted! 3. Qh5!! and white mates in 438. Actually, I have never played against Nxe4 on this website. I doubt many begginers even know about that move. Almost everyone plays the moves I discussed formerly, namely 2...Nc6 or 2...Bb4.
Thanks to Chess.com's live chess, I have been practicing my main opening for white, the bishops opening and vienna game. Often, I encountered 1. e4 e5 2. Bc4 Nf6 3. Nc3 Bb4!?. I went on Wikipedia and wikipedia gives the roy lopez line: 1. e4 e5 2. Nf3 Nc6 3. Bb5 Bc5 4.c3 Nf6.
Perhaps in my games I should play 4. Nf3!? leading to Kings gambit declined by transposition, or a Gambit if black plays ...Nxe4?!
Feel free to post comments on what you think is the right move in the position. Usually I play 4. Nge2 or d3.