Nath should aim to get battle cards early to gain Active Extension stacks quickly, the player should prioritize Draw panels until they have at minimum two battle cards.
Nath should deck low level and low cost battle cards in order to gain stacks of Active Extension as quickly as she can. Ideally using them when as safe as possible, preferably against units generated by Encounter panels or enemy players who've been weakened.
Rbits and Quick Restoration allow Nath to take very safe fights, often resulting in 1 and 0 damage taken respectively regardless of the opponent's ATK stat. However it may allow players to safely fight into a full stack Nath once.
I'm on Fire! can allow Nath to avoid taking a hit by KO'ing the defending unit before they can hit Nath. It is also a level 1 card, allowing for very quick stacks.
Tactical Retreat also enables safe fights, however it requires another player to fight Nath, which players may avoid doing.
Rainbow-Colored Circle is another cheap battle card Nath can use for Active Extension stacks, however the EVD buff will partially be negated by Nath losing EVD on use, causing it to primarily lower her DEF.
Because of Nath's reliance on battles, she will often take damage before reaching three. Portable Pudding functions both as a healing card and a battle card to allow Nath to gain a stack.
Do not be afraid of using Another Ultimate Weapon early for a stack, if Nath can reach 3 stacks it is likely she can regain all stars paid for earlier through KO'ing other players.
Nice Present is okay on paper, however will usually be less valuable than simply directly drawing a battle card.