In an assembly and methods for NOx reductant dosing with variable spray angle nozzle, according to various embodiments, a reductant dosage is calculated. A reductant delivery region in an exhaust stream area of an aftertreatment system and an actuation period may be specified. Based at least on the reductant delivery region and the actuation period, the reductant insertion assembly may be placed in a state for reductant delivery such that one of a first array of reductant insertion ports and a second array of reductant insertion ports is in an open position. The shape of the variable spray angle nozzle may define different levels. Different arrays of reductant delivery ports may have varying operating characteristics, such as diameter, number of ports, actuation time, and/or reagent delivery angle and may be activated based on reductant flow pressure and/or reductant flow velocity.