Lithium nitrate and sodium nitrate, when heated separately, respectively, give

$L{i}_{2}O,NaN{O}_2$

As per NCERT Lithium nitrate when heated gives lithium oxide, whereas other alkali metal  nitrates decompose to give the corresponding nitrite.

$4LiN{O}_3\to 2L{i}_{2}O+4N{O}_2+O_2$

$2NaN{O}_3\to NaN{O}_2+O_2$

However, the decomposition product of $NaN{O}_3$ are temperature dependent process as shown in the below reaction.

As temperature is not mentioned, we can go by