Constructing integrated multifunctional hydrogels with both high toughness and diverse functionalities is beneficial for the development of flexible antibacterial materials and wearable sensors. However, current hydrogels often fail to achieve a synergistic balance among toughness, antibacterial activity, and sensing responsiveness, limiting their practical applications. Herein, a "nano-bridge" strategy is proposed to fabricate a double-network hydrogel system (PHS-CT) composed of a covalent polyacrylamide network and a dynamic borate-crosslinked hydroxypropyl guar gum/sodium alginate network. The incorporated Cu-TA nanosheets serve not only as "structural bridges" to enhance the crosslinking density and mechanical performance (strain up to 1997.7%, toughness up to 1.53 MJ/m3), but also as "functional bridges" to enable photothermal conversion and improved antibacterial activity (bacterial killing rate of 99.0% against E. coli under NIR irradiation). In addition, benefiting from the dynamic reversibility of borate ester bonds as well as the re-forming capability of hydrogen bonds at the fracture interface, the hydrogel exhibits favorable self-healing ability (self-healing efficiency up to 91.0%), and can function as a flexible strain sensor capable of accurately detecting both large-scale and subtle deformations. This strategy provides a feasible strategy for constructing multifunctional dual-network hydrogels, and may be useful for photothermal antibacterial and flexible sensing applications.