The NCAA rules define "offensive personnel" to include "coaches not in the coaches' box" and then says that offensive personnel cannot interfere with a fielder making a play on the ball (9.5.1). So, in NCAA, a coach in the box is not liable for interference.
"Intentionally" doing something by anyone (coach or player) can be considered unsportsmanlike conduct. So, if a coach blatantly interfered (e.g., pushed a fielder), then it would be unsportsmanlike conduct no matter where the coach is positioned and the batter could be declared out and the coach could be ejected.
"Intentionally" doing something by anyone (coach or player) can be considered unsportsmanlike conduct. So, if a coach blatantly interfered (e.g., pushed a fielder), then it would be unsportsmanlike conduct no matter where the coach is positioned and the batter could be declared out and the coach could be ejected.