The upper and lower bounds of the time-delay due to the variations of some physical and geometrical characteristics of a nano-interconnect based on Multi Wall CNTs, suitable for the 32 and 22 nm technology, are evaluated. Interval Analysis is used to define the ranges of the of the p.u.l. parameters of a Transmission Line modeling the interconnect. The Vertex Analysis is then exploited on the parameter space to obtain in a reliable way the time-delay bounding without extensive and costly simulation burden. The obtained results are compared with those of scaled down copper-based structures.