While in Nogales, make sure you stop to have lunch or at least a snack. If you like Mexican food you are sure in for a treat. We had lunch at La Hacienda Del Caballo Rojo. The tortilla chips were fresh and crispy. The salsa was hot and spicey. The tortilla was freshly made. It was a great and an inexpensive lunch given the exchange rate.
Nogales is a relatively small town. Not quite the husle and bustle you would find in Tijuana. It's basically small scale Tijuana. You can stroll through the streets check out the markets for various leather goods, plates and cups, jewelry and clothing.
One of the primary reasons Americans come to Nogales is to shop, and one of the most colorful places to pick up a bargain is from the scores of street vendors who set up along the two blocks of Pasaje Morelos. This is a repainted alleyway which has been converted into an open-air pedestrian shopping strip. Even if you are "just looking", you will find Pasaje Moreles an interesting walk, although you may also find it to be a bit crowded.
There are also many finer shops throughout the city for those who are seeking something a little nicer.
You can get just about anything in Nogales. Some of the more popular, inexpensive items include luggage/leather goods, jewelry (especially silver), colognes/perfumes, liquor, prescription-type drugs, pottery, hand-crafted goods, quilts/throws, & bullhorns.
This is one of those touristy things that you'll find in many cities, similar to Tijuana. Whereas, I did get a picture with a donkey in Tijuana, I passed in Nogales. But, in case you're interested you know its always an option.
The closest thing Nogales has to a tourist site is Plaza Nogales, which is the plaza of the cathedral.