Admit that you and your band are sell-outs. In order to become successful, you have to come to terms with the fact that you're only concerned with mass appeal. Remember, Nickelback's only concern was getting on the radio, not creating art.
Commit to becoming a bland, generic lead singer. Singing in such a banal style requires concentration and hard work. If you have a dull band backing you up, this shouldn't be too hard.
Destroy your voice. For many, it is unnatural to sing in such a raspy voice. Luckily, scalding hot liquids and tobacco smoke ruin your larynx to create that distinctive sound. However, it appears as though Chad's voice was rough and ruined well before he became famous.
Sing in the same key in every song. Part of the appeal of Chad Kroeger's singing style is that he refuses to change his key in any song that he sings. Their guitarist has even admitted to sounding the same in every song, which is why they've had so much radio success.
Write sub-standard lyrics. Again, this may not appear to have anything to do with the sound of your voice, but you'd be surprised to find that bland lyrics force the singer into such a depression that he cannot help but to garble his singing voice.
Wear a cowboy hat. Chad Kroeger never plays a show without his cowboy hat and has threatened to fight fans who have grabbed it off his head. Though this doesn't directly affect your singing style, it's integral in reinforcing its mediocrity.