All plants absorb nitrate in some capacity. Plant uptake of nutrients corresponds with growth speed. Using high light and CO2 will speed up plant metabolism to uptake nutrients faster. In general, fast growing plants will absorb the most nutrients, so things like hornwort, amazon swords, and even java moss, will do the trick. Still, you need to provide all plants with the correct environment to thrive if you want to get the best results, growth, and nutrient removing capacities, so research your plants before purchasing and know what to expect.
Try the Marimo Moss Balls. They are very popular when it comes to plants that absorb most nitrates. Also, you can try duckweed, water sprite, anacharis elodea, frogbit, or water lettuce. As long as the plant grows fairly quickly and feeds on the nutrients water a great deal, it will make for a perfect nitrate-reducing plant.