"全国橄榄球联赛" can be translated as "National Rugby League" in English.
However, it's worth noting that "National Rugby League" is also the official name of a specific professional rugby league football competition in Australia and New Zealand. If you're referring to a national rugby league competition in another country, you might need to adjust the translation slightly to reflect the specific context, such as by adding the country's name (e.g., "China National Rugby League" for a hypothetical Chinese national rugby league). But in a general or context-free setting, "National Rugby League" is a common and acceptable translation for "全国橄榄球联赛".