The Price of Power card is perfectly tooled for Nath. The card can be very helpful at Norma levels 1-3, as many battle cards are Norma level 2 and most powerful ones are level 4. This will enable Nath to get a head start on gaining stacks of Active Extension.
Nice Present is a great card for Nath as it will increase the player's chance of drawing a battle card, if they do not have any in their possession.
Cards such as Rbits, Tactical Retreat,Quick Restoration, and I'm on Fire! are all very viable battle cards for Nath, as they do not aid the opponent much and are low level and cheap to use. These battle cards are also unable to counter Nath's Hyper if used by the opponent.
If the player is unfortunate enough not to start the game with one usable battle card to defend her weak stats, it is advisable to aim for Draw panels instead of Bonus panels.
HP is a very important aspect to Nath and strategizing, as are health cards such as Pudding and Quick Restoration. If Nath is at base extensions it doesn't affect her if opponents have healing because she's either star farming or she can use Another Ultimate Weapon to turn the tables to win. If Nath is at stock level 1 she will probably need healing because her 0 stats are nonthreatening and opponents will want to do deal damage while they can. At stock 2 and above, Nath will be desperately in need of a solution for attrition damage, and every point of healing becomes extremely valuable to preserve her high stats.
In the right circumstances, Mimic and Extension can be useful, however, their performance is mixed. Nath's Hyper is not bad, but expensive, which may cause a player to want another player's Hyper (which can technically be achieved with the treasure field event as well) however a player may also mimic Nath's Hyper. While Extension is useful as well, it is a shot in the dark as to which battle card will be drawn, but it will give Nath a single stock and is also useful if the enemy uses it themselves in an emergency, as it will power up Nath.
Marc herself can be an effective counter to Nath, as her Hyper, x16 Big Rocket, can be used to keep KOing Nath to prevent her from gaining stocks.
Forced Revival can be an effective card against Nath since without HP, Nath will likely be KO'd again, thus losing another stock of Active Extension.
It may be in the player's best interest to not attack Nath, if she is without Active Extensions stacks. Cards such as Tactical Retreat and Shield can only be used when Nath is attacked by another player, so not attacking will prevent her from leveling her passive.
Cards that KO, are the most effective against Nath such as Hypers like Gamble! or cards like Flamethrower, as they will instantly make her lose a stock of Active extension.