You're to that awfully infuriating track. However, you've done a lot since the last time (beaten Ryo, for instance) so you should find this less difficult.
Time Attack: Nevada Highway C
The longest version of the track, difficult and dangerous as usual. You must learn it by heart. If you drive something light, look out on the bumps. No golden rules can be established here, the smallest mistake will send you hurtling into a wall. It goes without saying you'll have to go really fast to win.
Time Attack: Nevada Highway B
A short fragment of C track. It's definitely easier, just watch out on the bumps and near the end.
Time Attack: Nevada Highway A
Another piece of track C, although there's a lot less time to make a mistake. Watch out on the U-turns. Don't ram the roadsigns and under no circumstances drive off the road.
Top Speed Run: Nevada Highway A
Same as above, but with checkpoints, 6 to be exact. You have enough nitrous, of course, use it only at the checkpoints after the turns you've had to brake before. Apart from that, winning is a question of dexterity.
Top Speed Run: Nevada Highway B
You know this perfectly, there's only 4 checkpoints, three difficult turns and enough nitro for the whole thing.
Top Speed Run: Nevada Highway C
The longest version of the track, 10 checkpoints. You'll have to drive as fast as in the Time Attack because you don't have enough nitro to make up for the loss of speed. Even so, an emergency brake is OK now and then.