Cactus pear is an important forage for ruminant animals in semi-arid regions, though its cultivation typically involves low technological input. This study evaluated the impact of inoculation with plant growth-promoting bacteria (PGPB) on two cactus pear cultivars (Baiana and Doce) under nitrogen (N) fertilization levels in semi-arid soil. Strains of Bacillus subtilis (IPACC29 and IPACC26) and Paenibacillus sp. (IPACC55 and IPACC38), a commercial inoculant based on Azospirillum brasilense (AbV5 + AbV6) (AB), and a control without inoculation were tested in combination with three nitrogen (N) doses (0, 50, and 100%). PGPB inoculation enhanced nitrogen metabolism and plant growth, especially at 50% N. In the Baiana cultivar, all inoculants increased root dry mass at 50% N. IPACC29 additionally increased cladode dry mass. IPACC26 improved nitrogen and soluble protein content in cladodes and stimulated nitrate reductase activity in roots, while IPACC55 increased root ammonium content and soluble carbohydrate levels in cladodes. For the Doce cultivar, all inoculants raised cladode dry mass and enhanced root levels of soluble amino-nitrogen and proteins at 50% N. Only IPACC38 significantly increased root dry mass. IPACC29 and AB also improved nitrogen accumulation and protein content in cladodes, along with ammonium levels in roots. Our findings indicate that, overall, the IPACC29 (B. subtilis) and IPACC38 (Paenibacillus sp.) strains, when combined with 50% N, stand out as the most promising for enhancing the growth of Nopalea cactus pear. Consequently, they show strong potential as bioinoculants, contributing to the sustainable cultivation of this crop in semi-arid environments.