No Chart. Sorry.
Tactical Units can be 3-person Fire Teams or 3-drone Pods.
Simply put
1 Agent = 1 D6 Quality TacU
2 Agents = 1 D8 Quality TacU or 2 D6 Q TacU
3 Agents = 1 D10 Quality TacU or combination of the above.
4+ Agents = Combo of above
Specialists and Heavy Support Units (HSU) are subcategories of TacU that are only available as D8 or D10 Quality, but the same rules apply.