My sister had clipped her toe nails, and had been did yard work, tonite she noticed her toe was red and slightly swollen should she see a Doctor?

Not a bad idea. An antibiotic would help her. She could try soaking foot in warm water and Epsom salt and applying a topical antibiotic. Also make sure to clean the feet obviously. But, if you don't see improvement in a day or two then get the oral antibiotic.
Not So Fast. Sounds like the toe is beginning to show signs of inflammation, not necessarily infection. Best to clean toe thoroughly and examine it carefully for cuts in the tissue. Treat any cuts with a topical antibiotic. Apply a small ice pack occasionally, for sever minutes at a time. If the redness an swelling continues then call the doctor.