The present paper discusses the occurrence, structure, and complexity of the postmodifier in the Nigerian English noun phrase (NP) showing tendencies for structural simplification. It also compares its findings with patterns in British, Ghanaian, Singaporean, Honk Kong varieties. The paper shows how variables representing syntactic function, register, and weight shed light on specific contexts where we might or might not find (1) NP with or without a postmodifier (2) a clausal or phrasal postmodifier, and (3) a simple or a complex postmodifier. In addition, the paper shows that the extent of variation among different varieties of English is dependent on variables crucial to the construction choices being investigated. For instance, in (1), a postmodifier is realised while no postmodifier is realised in (2). (1) My car which I just bought last week has been stolen, and (2) My car has been stolen.The NP in (1) is structurally complex because it realises the clausal type of post modifier, ‘which I just bought last week’. Meanwhile in (2), the NP (the car) lacks a postmodifier. In other words, the occurrence viz-a-viz non-occurrence of a postmodifier contributes to the overall structural and semantic complexity of the entire noun phrases, irrespective of the syntactic positions of the NP. Quantitative analyses of 8897 NPs indicate that in Nigerian NPs, a postmodifier is more unlikely to occur (61 %) than not (39 %). Further analyses show that prepositional phrase (57 %), rather than clause (32 %) or adjective (9 %) or adverbials (2 %), is the most preferred structural postmodifier type. It is also shown that realised postmodifiers are more likely to be structured in two-to-four words (51 %) than four-words above. As for the predictive strength of variables studied, syntactic function is found to edge register in asserting influence and explaining different scenarios and contexts where we might or might not find a postmodifier, together with its structural type and weight. In other words, register, which is reputed as a significant indicator of structural variation (Biber, 2007; De Haan, Pieter. 1993. Sentence Length in Running Text. In Souter, C. & E. Atwell (), Corpus-Based Computational Linguistics , 147–161. Amsterdam: Rodopi; Schilk and Schaub, 2016) is outweighed by syntactic function. The study further attests that significant structural simplification is largely present in the postmodifier structure of the Nigerian English noun phrase.