Benign Lipomatous Lesion (e.g., Lipoma): Given the nodule's isoechoic appearance to adjacent fat and its small size (8 x 5 mm), a benign lipomatous lesion is a plausible diagnosis. The hypervascular nature on color Doppler could be seen in some lipomas, especially if they are undergoing changes or are of a specific subtype.

Hemangioma: A hypervascular lesion, as indicated by color Doppler, could suggest a hemangioma, which is a common benign vascular tumor. These can appear in the skin and subcutaneous tissue and may present as small nodules.
Pyogenic Granuloma: Although typically more friable and prone to bleeding, pyogenic granulomas can appear as small, hypervascular nodules on the skin, including the nose. They are benign but can be problematic due to bleeding.
Dermatofibroma: A dermatofibroma could present as a small nodule and might show increased vascularity. However, they are usually less vascular than what might be expected in a highly hypervascular lesion.

Basal Cell Carcinoma (BCC): Although less likely given the description, BCC is a common skin cancer that can present as a small nodule on the nose. It's crucial to consider due to its potential for local destruction if left untreated.
Squamous Cell Carcinoma (SCC): Similar to BCC, SCC is a skin cancer that can appear as a small nodule. It's more aggressive than BCC and can metastasize, making it a critical diagnosis not to miss.
Merkel Cell Carcinoma: A rare but aggressive skin cancer that can present as a small, firm nodule. Its hypervascular nature could be consistent with this diagnosis, and it's essential to consider due to its high risk of metastasis.

Glomus Tumor: A rare, benign tumor that can appear in the skin, often presenting as a small, painful nodule. It could be hypervascular and is more commonly found under the nail but can occur elsewhere, including the nose.
Kaposi's Sarcoma: A rare cancer that can present as skin lesions, which might appear as small nodules. It's more common in immunocompromised individuals and could show hypervascularity on imaging.
Metastatic Disease: Rarely, a metastasis from another primary cancer could present as a small nodule on the nose. This would be extremely uncommon but is a consideration in patients with a known history of cancer.