The ornamental design for an ergonomicknife handle, as shown and described.
FIG. 1 is a left side view of my new design, the right side being a mirror image thereof;
FIG. 2 is a front view thereof, taken in the direction of arrows 2-2;
FIG. 3 is a top view thereof, taken in the direction of arrows 3-3; and,
FIG. 4 is a bottom view thereof, taken in the direction of arrows 4-4.
The broken lines are for the purpose of illustrating relationship with functional parts that may be used with our design, and form no part of the claim design.