Are there any modern age pieces that excel at getting to the back lines to take this guy out before you have to deal with his heavy hitters?

copycat works pretty well

Quinjet + Cap (ffoa #006r) is a great combo! Jet doesn't reduce movement for carrying and Cap lets you move 6 squares for free and then move another 11 for a total of 17 squares in one round, so depending on the map you chose you could base NHP on your very first turn....

WXM Shatterstar, pair him with someone who can MC friendlies and someone who can tag along.

This is an article related to Nighthawk Prime and quiet interesting. Hope you can find your answers.

http://www.hcrealms.com/forum/showthread.php?t=555939

When I won my Streaky at a World Finest event, I thought of him being a good way to threaten Nighthawk. You push Straky to get into Flurry and when Nighthawk uses sidestep, you place Streaky next to him

Fast Forces Lockjaw at 25 points is great at carrying your force right into Nighthawk's face, and then tying him up with Plasticity.

Depending on map choice, white rabbit has worked wonders time and time again for me. Got a map with a lot of blocking? Double power action to move the majority of the map and sidestep into place. otherwise she can still base him turn 2 simply off her movement and sidestep.

agent 37. or jltw lex luthor.

I know this answer will be of limited use, especially if we're talking a 300 point game, but I sure had fun basing (and crushing) Nighthawk prime with:

since you have to be adjacent for this to work it doesn't really help in getting adjacent to him.

My biggest combo for dealing with Nighthawk that will still be modern age legal after 6/1 was 3D-Man with a piece TK like Mercury.

Black Talon, Shatterstar, Peggy Carter Prime. Choose choose shape change with peggy, Mind Control Shatterstar to port over there with peggy and then flurry blades his butt into bolivion.

War Machine prime + Agent 13. Be sure to push Agent 13 to her second click. Then give War Machine a DPA, carry Agent 13 with a move action, then again with a running shot, dropping her next to Nighthawk, then finishing him off with a 5-damage ranged attack, all in one turn.

It's a theme team so Agent 13 can prob you if you miss.