In the Madden NFL Mobile games your coach offered passive bonuses to your team in certain situations, and you leveled up coaches by obtaining multiple versions of that coach. In Madden NFL Overdrive you will not have to obtain a coach through a pack but instead select one from a group at the start of the game.
As you progress through the game and level up your coach you will gain access to more coaches, each with their own set of additional plays and tactics. Filling up the Tactics meter at the bottom of the screen with white nodes will unlock tactical choices on the playcall screen. Tactics are broken up into three different categories (Attribute Buffs, Adjustments, and Global Scoring Changes) and each costs a different amount based on its ability to improve your chances to win a game.