B. nuchalis can be identified by checking 21(23) mid body rows which are always 19 in other two similar looking species.
Average length- 90cm.
Maximum length- Approx 120cm.
Laterally flattened long body. Scales smooth, long shaped and obliquely arranged. Top dosral scales along the vertebra larger than side scales and of hexagonal shape. Dorsal color brown, yellowish or brown mixed with reddish. About 90-100 dark brown or dark reddish bars present in most of the dorsal surface which become faint posterior body. or cross lines found from head to tail. These markings are broadest on vertebral region.
Belly color cream with blackish or dark brown speckles more dense on on the outer edge of ventral scales. Subcaudal scales paired in zig-zag manner.
Head triangular with rounded edge; clearly broader than neck. Top of the head of similar to dorsal color. One black streak runs behind the eye to end of the head. Large eyes with vertical pupil.
Long and thin tail typically like other arboreal snakes with pointed tip. Dorsal body patterns continue to tail in faint form.